Stable C and N Isotope Composition of Primary Producers and Consumers Along an Estuarine Salinity Gradient: Tracing Mixing Patterns and Trophic Discrimination

Erik Kristensen*, Cintia O. Quintana, Thomas Valdemarsen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The mixing pattern along a summer salinity gradient in the estuary Odense Fjord was evaluated using nutrient concentrations as well as 13C and 15N isotope signatures of suspended and sediment organic matter, immobile macrophytes (Fucus vesiculosus and Ruppia maritima), and benthic fauna (Mya arenaria, Hediste (Nereis) diversicolor, and Arenicola marina). Trophic discrimination (Δ13C and Δ15N) of the infaunal consumers (suspension feeders and detritivores) was assessed from the obtained mixing patterns along the estuarine gradient. Correspondence between salinity, DIC, and DIN in Odense Fjord implies conservative mixing as also evident from linear relationships between salinity and δ13C and δ15N signatures of most living organic pools. Isotope signatures of suspended organic matter (i.e., diatoms) indicate that the river to marine DIC and DIN end-members have daily/weekly δ13C and δ15N averages during summer from − 10 to 0‰ and 10–12 to 0–5‰, respectively. Stable isotope signatures of long-lived macrophytes stationary at specific locations in Odense Fjord showed δ13C levels that were about 7‰ higher than for suspended particles and 3–4‰ higher than for sediment organic matter, while no such difference was evident for δ15N. The food of invertebrate consumers (M. arenaria, H. diversicolor, and A. marina) determined from the estuarine δ13C and δ15N patterns provided the first ever reported trophic discrimination of these animals. Thus, Δ13C was 1.9, 1.6, and 1.3‰ and Δ15N was 4.4, 5.0, and 3.5‰ for the three species, respectively. Accordingly, benthic suspension and deposit feeders in Odense Fjord are largely supported by a diet consisting of benthic and pelagic microalgae, however, with a possible slight shift in diet proportions or to other food sources in the lower reaches of the estuarine gradient.

Original languageEnglish
JournalEstuaries and Coasts
Volume42
Issue number1
Pages (from-to)144-156
ISSN1559-2723
DOIs
Publication statusPublished - Jan 2019

Fingerprint

fjord
Mya arenaria
isotopes
organic matter
isotope
salinity
macrophytes
marina
Ruppia maritima
Fucus vesiculosus
sediments
Bacillariophyceae
detritivores
summer
diet
microalgae
deposit feeder
stable isotopes
food
nutrient content

Keywords

  • Consumers
  • Estuarine mixing
  • Isotope fractionation
  • Primary producers
  • Stable C and N isotopes
  • Trophic discrimination

Cite this

@article{ed81118714984ac9b8f3d6a768d9c661,
title = "Stable C and N Isotope Composition of Primary Producers and Consumers Along an Estuarine Salinity Gradient: Tracing Mixing Patterns and Trophic Discrimination",
abstract = "The mixing pattern along a summer salinity gradient in the estuary Odense Fjord was evaluated using nutrient concentrations as well as 13C and 15N isotope signatures of suspended and sediment organic matter, immobile macrophytes (Fucus vesiculosus and Ruppia maritima), and benthic fauna (Mya arenaria, Hediste (Nereis) diversicolor, and Arenicola marina). Trophic discrimination (Δ13C and Δ15N) of the infaunal consumers (suspension feeders and detritivores) was assessed from the obtained mixing patterns along the estuarine gradient. Correspondence between salinity, DIC, and DIN in Odense Fjord implies conservative mixing as also evident from linear relationships between salinity and δ13C and δ15N signatures of most living organic pools. Isotope signatures of suspended organic matter (i.e., diatoms) indicate that the river to marine DIC and DIN end-members have daily/weekly δ13C and δ15N averages during summer from − 10 to 0‰ and 10–12 to 0–5‰, respectively. Stable isotope signatures of long-lived macrophytes stationary at specific locations in Odense Fjord showed δ13C levels that were about 7‰ higher than for suspended particles and 3–4‰ higher than for sediment organic matter, while no such difference was evident for δ15N. The food of invertebrate consumers (M. arenaria, H. diversicolor, and A. marina) determined from the estuarine δ13C and δ15N patterns provided the first ever reported trophic discrimination of these animals. Thus, Δ13C was 1.9, 1.6, and 1.3‰ and Δ15N was 4.4, 5.0, and 3.5‰ for the three species, respectively. Accordingly, benthic suspension and deposit feeders in Odense Fjord are largely supported by a diet consisting of benthic and pelagic microalgae, however, with a possible slight shift in diet proportions or to other food sources in the lower reaches of the estuarine gradient.",
keywords = "Consumers, Estuarine mixing, Isotope fractionation, Primary producers, Stable C and N isotopes, Trophic discrimination",
author = "Erik Kristensen and Quintana, {Cintia O.} and Thomas Valdemarsen",
year = "2019",
month = "1",
doi = "10.1007/s12237-018-0460-1",
language = "English",
volume = "42",
pages = "144--156",
journal = "Estuaries and Coasts",
issn = "1559-2723",
publisher = "Springer",
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}

Stable C and N Isotope Composition of Primary Producers and Consumers Along an Estuarine Salinity Gradient : Tracing Mixing Patterns and Trophic Discrimination. / Kristensen, Erik; Quintana, Cintia O.; Valdemarsen, Thomas.

In: Estuaries and Coasts, Vol. 42, No. 1, 01.2019, p. 144-156.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Stable C and N Isotope Composition of Primary Producers and Consumers Along an Estuarine Salinity Gradient

T2 - Tracing Mixing Patterns and Trophic Discrimination

AU - Kristensen, Erik

AU - Quintana, Cintia O.

AU - Valdemarsen, Thomas

PY - 2019/1

Y1 - 2019/1

N2 - The mixing pattern along a summer salinity gradient in the estuary Odense Fjord was evaluated using nutrient concentrations as well as 13C and 15N isotope signatures of suspended and sediment organic matter, immobile macrophytes (Fucus vesiculosus and Ruppia maritima), and benthic fauna (Mya arenaria, Hediste (Nereis) diversicolor, and Arenicola marina). Trophic discrimination (Δ13C and Δ15N) of the infaunal consumers (suspension feeders and detritivores) was assessed from the obtained mixing patterns along the estuarine gradient. Correspondence between salinity, DIC, and DIN in Odense Fjord implies conservative mixing as also evident from linear relationships between salinity and δ13C and δ15N signatures of most living organic pools. Isotope signatures of suspended organic matter (i.e., diatoms) indicate that the river to marine DIC and DIN end-members have daily/weekly δ13C and δ15N averages during summer from − 10 to 0‰ and 10–12 to 0–5‰, respectively. Stable isotope signatures of long-lived macrophytes stationary at specific locations in Odense Fjord showed δ13C levels that were about 7‰ higher than for suspended particles and 3–4‰ higher than for sediment organic matter, while no such difference was evident for δ15N. The food of invertebrate consumers (M. arenaria, H. diversicolor, and A. marina) determined from the estuarine δ13C and δ15N patterns provided the first ever reported trophic discrimination of these animals. Thus, Δ13C was 1.9, 1.6, and 1.3‰ and Δ15N was 4.4, 5.0, and 3.5‰ for the three species, respectively. Accordingly, benthic suspension and deposit feeders in Odense Fjord are largely supported by a diet consisting of benthic and pelagic microalgae, however, with a possible slight shift in diet proportions or to other food sources in the lower reaches of the estuarine gradient.

AB - The mixing pattern along a summer salinity gradient in the estuary Odense Fjord was evaluated using nutrient concentrations as well as 13C and 15N isotope signatures of suspended and sediment organic matter, immobile macrophytes (Fucus vesiculosus and Ruppia maritima), and benthic fauna (Mya arenaria, Hediste (Nereis) diversicolor, and Arenicola marina). Trophic discrimination (Δ13C and Δ15N) of the infaunal consumers (suspension feeders and detritivores) was assessed from the obtained mixing patterns along the estuarine gradient. Correspondence between salinity, DIC, and DIN in Odense Fjord implies conservative mixing as also evident from linear relationships between salinity and δ13C and δ15N signatures of most living organic pools. Isotope signatures of suspended organic matter (i.e., diatoms) indicate that the river to marine DIC and DIN end-members have daily/weekly δ13C and δ15N averages during summer from − 10 to 0‰ and 10–12 to 0–5‰, respectively. Stable isotope signatures of long-lived macrophytes stationary at specific locations in Odense Fjord showed δ13C levels that were about 7‰ higher than for suspended particles and 3–4‰ higher than for sediment organic matter, while no such difference was evident for δ15N. The food of invertebrate consumers (M. arenaria, H. diversicolor, and A. marina) determined from the estuarine δ13C and δ15N patterns provided the first ever reported trophic discrimination of these animals. Thus, Δ13C was 1.9, 1.6, and 1.3‰ and Δ15N was 4.4, 5.0, and 3.5‰ for the three species, respectively. Accordingly, benthic suspension and deposit feeders in Odense Fjord are largely supported by a diet consisting of benthic and pelagic microalgae, however, with a possible slight shift in diet proportions or to other food sources in the lower reaches of the estuarine gradient.

KW - Consumers

KW - Estuarine mixing

KW - Isotope fractionation

KW - Primary producers

KW - Stable C and N isotopes

KW - Trophic discrimination

U2 - 10.1007/s12237-018-0460-1

DO - 10.1007/s12237-018-0460-1

M3 - Journal article

AN - SCOPUS:85053536206

VL - 42

SP - 144

EP - 156

JO - Estuaries and Coasts

JF - Estuaries and Coasts

SN - 1559-2723

IS - 1

ER -